使用ESP32驱动QMA7981读取三轴加速度（带例程）

1.简介

ESP32是国产乐鑫公司生产的32位单片机，双核240MHz，带有蓝牙和wifi功能，本例中使用的是ESP32-S模组。QMA7981是国产矽睿公司生产的三轴加速度传感器（支持国产，从我做起）。本例中使用的开发环境是VSCODE安装ESP-IDF插件。

2.硬件连接

ESP32-S

QMA7981

3.使用方法

首先配置ESP-IDF的配置文件，将I2C使用的SDA和SCL引脚配置为和电路中一样。在VSCODE主界面按F1，在弹出的搜索框内选择ESP-IDF SDK配置编辑器。在左边选择Example Configuration，在右边的SCL GPIO Num和SDA GPIO Num中输入自己的硬件连接的IO口，点击右上角的保存。

使用QMA7981传感器的流程是，首先进行I2C初始化，然后将QMA7981设置为active状态，然后配置QMA7981的量程（默认是2g，由于我是为了计算倾角，只需要用到最低的2g，所以省略了这一步），然后就可以使用存储3轴加速度值的寄存器地址读取三轴加速度值了。以下是代码：

#include <stdio.h>
#include <stdlib.h>
#include "esp_log.h"
#include "driver/i2c.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
static const char *TAG = "i2c-simple-example";

#define I2C_MASTER_SCL_IO           CONFIG_I2C_MASTER_SCL      /*!< GPIO number used for I2C master clock */
#define I2C_MASTER_SDA_IO           CONFIG_I2C_MASTER_SDA      /*!< GPIO number used for I2C master data  */
#define I2C_MASTER_NUM              0           /*!< I2C master i2c port number, the number of i2c peripheral interfaces available will depend on the chip */
#define I2C_MASTER_FREQ_HZ          400000                     /*!< I2C master clock frequency */
#define I2C_MASTER_TX_BUF_DISABLE   0                          /*!< I2C master doesn't need buffer */
#define I2C_MASTER_RX_BUF_DISABLE   0                          /*!< I2C master doesn't need buffer */
#define I2C_MASTER_TIMEOUT_MS       1000

#define QMA7981_ADDR                        0x12        /*!< Slave address of the QMA7981 */
#define QMA7981_WHO_AM_I_REG_ADDR           0x00        /*!< Register addresses of the "who am I" register */
#define QMA7981_PWR_MGMT_1_REG_ADDR         0x11        /*!< Register addresses of the power managment register */

#define QMA7981_DXM 0x01											//QMA7981寄存器X轴加速度地址
#define QMA7981_DYM 0x03											//QMA7981寄存器Y轴加速度地址
#define QMA7981_DZM 0x05											//QMA7981寄存器Z轴加速度地址

#define QMA7981_start_convert_cmd 0xC0					//设置QMA7981为active模式的指令

#define QMA7981_MAX_VALUE 0x1FFF							//满量程读数

/**@brief Read a sequence of bytes from a QMA7981 sensor registers*/
static esp_err_t QMA7981_register_read(uint8_t reg_addr, uint8_t *data, size_t len)
{
return i2c_master_write_read_device(I2C_MASTER_NUM, QMA7981_ADDR, &reg_addr, 1, data, len, I2C_MASTER_TIMEOUT_MS / portTICK_RATE_MS);
}

/**@brief Write a byte to a QMA7981 sensor register*/
static esp_err_t QMA7981_register_write_byte(uint8_t reg_addr, uint8_t data)
{
int ret;
uint8_t write_buf[2] = {reg_addr, data};
ret = i2c_master_write_to_device(I2C_MASTER_NUM, QMA7981_ADDR, write_buf, sizeof(write_buf), I2C_MASTER_TIMEOUT_MS / portTICK_RATE_MS);
return ret;
}

/**@brief i2c master initialization*/
static esp_err_t i2c_master_init(void)
{

int i2c_master_port = I2C_MASTER_NUM;

i2c_config_t conf = {
    .mode = I2C_MODE_MASTER,
    .sda_io_num = I2C_MASTER_SDA_IO,
    .scl_io_num = I2C_MASTER_SCL_IO,
    .sda_pullup_en = GPIO_PULLUP_ENABLE,
    .scl_pullup_en = GPIO_PULLUP_ENABLE,
    .master.clk_speed = I2C_MASTER_FREQ_HZ,
};

i2c_param_config(i2c_master_port, &conf);
return i2c_driver_install(i2c_master_port, conf.mode, I2C_MASTER_RX_BUF_DISABLE, I2C_MASTER_TX_BUF_DISABLE, 0);
}

void app_main(void)
{
    uint8_t data[2];
    
    int16_t XA;
    int16_t YA;
    int16_t ZA;
    
    float X_AXIS_A;
    float Y_AXIS_A;
    float Z_AXIS_A;
    
    ESP_ERROR_CHECK(i2c_master_init());		//初始化I2C
    ESP_LOGI(TAG, "I2C initialized successfully");
    ESP_ERROR_CHECK(QMA7981_register_read(QMA7981_WHO_AM_I_REG_ADDR, data, 1));		//读取设备ID，正常是0xE7
    ESP_LOGI(TAG, "WHO_AM_I = %X", data[0]);
    ESP_ERROR_CHECK(QMA7981_register_write_byte(QMA7981_PWR_MGMT_1_REG_ADDR, QMA7981_start_convert_cmd));		//设置为active模式
    
    while(1)
    {	//读取和转换
        ESP_ERROR_CHECK(QMA7981_register_read(QMA7981_DXM, data, 2));
        XA = (data[0] & 0xFC) | (data[1]<< 8);
        ESP_ERROR_CHECK(QMA7981_register_read(QMA7981_DYM, data, 2));
        YA = (data[0] & 0xFC) | (data[1]<< 8);
        ESP_ERROR_CHECK(QMA7981_register_read(QMA7981_DZM, data, 2));
        ZA = (data[0] & 0xFC) | (data[1]<< 8);
        
        XA /= 4;
        YA /= 4;
        ZA /= 4;
        
        X_AXIS_A = (float) XA / QMA7981_MAX_VALUE * 2;
        Y_AXIS_A = (float) YA / QMA7981_MAX_VALUE * 2;
        Z_AXIS_A = (float) ZA / QMA7981_MAX_VALUE * 2;
        printf("X_RAW = %d , Y_RAW = %d , Z_RAW = %d . \n", XA, YA, ZA);
        printf("X_A = %.3f g, Y_A = %.3f g, Z_A = %.3f g. \n", X_AXIS_A, Y_AXIS_A, Z_AXIS_A);
        vTaskDelay(1000 / portTICK_PERIOD_MS);
    }
}

标签：i2c,例程,ESP32,三轴,MASTER,master,I2C,QMA7981,define
来源： https://www.cnblogs.com/sora6A/p/16538918.html